"""Python part of the warnings subsystem.""" # Note: function level imports should *not* be used # in this module as it may cause import lock deadlock. # See bug 683658. import linecache import sys import types __all__ = ["warn", "showwarning", "formatwarning", "filterwarnings", "resetwarnings", "catch_warnings"] def warnpy3k(message, category=None, stacklevel=1): """Issue a deprecation warning for Python 3.x related changes. Warnings are omitted unless Python is started with the -3 option. """ if sys.py3kwarning: if category is None: category = DeprecationWarning warn(message, category, stacklevel+1) def _show_warning(message, category, filename, lineno, file=None, line=None): """Hook to write a warning to a file; replace if you like.""" if file is None: file = sys.stderr try: file.write(formatwarning(message, category, filename, lineno, line)) except IOError: pass # the file (probably stderr) is invalid - this warning gets lost. # Keep a working version around in case the deprecation of the old API is # triggered. showwarning = _show_warning def formatwarning(message, category, filename, lineno, line=None): """Function to format a warning the standard way.""" s = "%s:%s: %s: %s\n" % (filename, lineno, category.__name__, message) line = linecache.getline(filename, lineno) if line is None else line if line: line = line.strip() s += " %s\n" % line return s def filterwarnings(action, message="", category=Warning, module="", lineno=0, append=0): """Insert an entry into the list of warnings filters (at the front). Use assertions to check that all arguments have the right type.""" import re assert action in ("error", "ignore", "always", "default", "module", "once"), "invalid action: %r" % (action,) assert isinstance(message, basestring), "message must be a string" assert isinstance(category, (type, types.ClassType)), \ "category must be a class" assert issubclass(category, Warning), "category must be a Warning subclass" assert isinstance(module, basestring), "module must be a string" assert isinstance(lineno, int) and lineno >= 0, \ "lineno must be an int >= 0" item = (action, re.compile(message, re.I), category, re.compile(module), lineno) if append: filters.append(item) else: filters.insert(0, item) def simplefilter(action, category=Warning, lineno=0, append=0): """Insert a simple entry into the list of warnings filters (at the front). A simple filter matches all modules and messages. """ assert action in ("error", "ignore", "always", "default", "module", "once"), "invalid action: %r" % (action,) assert isinstance(lineno, int) and lineno >= 0, \ "lineno must be an int >= 0" item = (action, None, category, None, lineno) if append: filters.append(item) else: filters.insert(0, item) def resetwarnings(): """Clear the list of warning filters, so that no filters are active.""" filters[:] = [] class _OptionError(Exception): """Exception used by option processing helpers.""" pass # Helper to process -W options passed via sys.warnoptions def _processoptions(args): for arg in args: try: _setoption(arg) except _OptionError, msg: print >>sys.stderr, "Invalid -W option ignored:", msg # Helper for _processoptions() def _setoption(arg): import re parts = arg.split(':') if len(parts) > 5: raise _OptionError("too many fields (max 5): %r" % (arg,)) while len(parts) < 5: parts.append('') action, message, category, module, lineno = [s.strip() for s in parts] action = _getaction(action) message = re.escape(message) category = _getcategory(category) module = re.escape(module) if module: module = module + '$' if lineno: try: lineno = int(lineno) if lineno < 0: raise ValueError except (ValueError, OverflowError): raise _OptionError("invalid lineno %r" % (lineno,)) else: lineno = 0 filterwarnings(action, message, category, module, lineno) # Helper for _setoption() def _getaction(action): if not action: return "default" if action == "all": return "always" # Alias for a in ('default', 'always', 'ignore', 'module', 'once', 'error'): if a.startswith(action): return a raise _OptionError("invalid action: %r" % (action,)) # Helper for _setoption() def _getcategory(category): import re if not category: return Warning if re.match("^[a-zA-Z0-9_]+$", category): try: cat = eval(category) except NameError: raise _OptionError("unknown warning category: %r" % (category,)) else: i = category.rfind(".") module = category[:i] klass = category[i+1:] try: m = __import__(module, None, None, [klass]) except ImportError: raise _OptionError("invalid module name: %r" % (module,)) try: cat = getattr(m, klass) except AttributeError: raise _OptionError("unknown warning category: %r" % (category,)) if not issubclass(cat, Warning): raise _OptionError("invalid warning category: %r" % (category,)) return cat # Code typically replaced by _warnings def warn(message, category=None, stacklevel=1): """Issue a warning, or maybe ignore it or raise an exception.""" # Check if message is already a Warning object if isinstance(message, Warning): category = message.__class__ # Check category argument if category is None: category = UserWarning assert issubclass(category, Warning) # Get context information try: caller = sys._getframe(stacklevel) except ValueError: globals = sys.__dict__ lineno = 1 else: globals = caller.f_globals lineno = caller.f_lineno if '__name__' in globals: module = globals['__name__'] else: module = "" filename = globals.get('__file__') if filename: fnl = filename.lower() if fnl.endswith((".pyc", ".pyo")): filename = filename[:-1] else: if module == "__main__": try: filename = sys.argv[0] except AttributeError: # embedded interpreters don't have sys.argv, see bug #839151 filename = '__main__' if not filename: filename = module registry = globals.setdefault("__warningregistry__", {}) warn_explicit(message, category, filename, lineno, module, registry, globals) def warn_explicit(message, category, filename, lineno, module=None, registry=None, module_globals=None): lineno = int(lineno) if module is None: module = filename or "" if module[-3:].lower() == ".py": module = module[:-3] # XXX What about leading pathname? if registry is None: registry = {} if isinstance(message, Warning): text = str(message) category = message.__class__ else: text = message message = category(message) key = (text, category, lineno) # Quick test for common case if registry.get(key): return # Search the filters for item in filters: action, msg, cat, mod, ln = item if ((msg is None or msg.match(text)) and issubclass(category, cat) and (mod is None or mod.match(module)) and (ln == 0 or lineno == ln)): break else: action = defaultaction # Early exit actions if action == "ignore": registry[key] = 1 return # Prime the linecache for formatting, in case the # "file" is actually in a zipfile or something. linecache.getlines(filename, module_globals) if action == "error": raise message # Other actions if action == "once": registry[key] = 1 oncekey = (text, category) if onceregistry.get(oncekey): return onceregistry[oncekey] = 1 elif action == "always": pass elif action == "module": registry[key] = 1 altkey = (text, category, 0) if registry.get(altkey): return registry[altkey] = 1 elif action == "default": registry[key] = 1 else: # Unrecognized actions are errors raise RuntimeError( "Unrecognized action (%r) in warnings.filters:\n %s" % (action, item)) # Warn if showwarning() does not support the 'line' argument. # Don't use 'inspect' as it relies on an extension module, which break the # build thanks to 'warnings' being imported by setup.py. fxn_code = None if hasattr(showwarning, 'func_code'): fxn_code = showwarning.func_code elif hasattr(showwarning, '__func__'): fxn_code = showwarning.__func__.func_code if fxn_code: args = fxn_code.co_varnames[:fxn_code.co_argcount] CO_VARARGS = 0x4 if 'line' not in args and not fxn_code.co_flags & CO_VARARGS: showwarning_msg = ("functions overriding warnings.showwarning() " "must support the 'line' argument") if message == showwarning_msg: _show_warning(message, category, filename, lineno) else: warn(showwarning_msg, DeprecationWarning) # Print message and context showwarning(message, category, filename, lineno) class WarningMessage(object): """Holds the result of a single showwarning() call.""" _WARNING_DETAILS = ("message", "category", "filename", "lineno", "file", "line") def __init__(self, message, category, filename, lineno, file=None, line=None): local_values = locals() for attr in self._WARNING_DETAILS: setattr(self, attr, local_values[attr]) self._category_name = category.__name__ if category else None def __str__(self): return ("{message : %r, category : %r, filename : %r, lineno : %s, " "line : %r}" % (self.message, self._category_name, self.filename, self.lineno, self.line)) class catch_warnings(object): """A context manager that copies and restores the warnings filter upon exiting the context. The 'record' argument specifies whether warnings should be captured by a custom implementation of warnings.showwarning() and be appended to a list returned by the context manager. Otherwise None is returned by the context manager. The objects appended to the list are arguments whose attributes mirror the arguments to showwarning(). The 'module' argument is to specify an alternative module to the module named 'warnings' and imported under that name. This argument is only useful when testing the warnings module itself. """ def __init__(self, record=False, module=None): """Specify whether to record warnings and if an alternative module should be used other than sys.modules['warnings']. For compatibility with Python 3.0, please consider all arguments to be keyword-only. """ self._record = record self._module = sys.modules['warnings'] if module is None else module self._entered = False def __repr__(self): args = [] if self._record: args.append("record=True") if self._module is not sys.modules['warnings']: args.append("module=%r" % self._module) name = type(self).__name__ return "%s(%s)" % (name, ", ".join(args)) def __enter__(self): if self._entered: raise RuntimeError("Cannot enter %r twice" % self) self._entered = True self._filters = self._module.filters self._module.filters = self._filters[:] self._showwarning = self._module.showwarning if self._record: log = [] def showwarning(*args, **kwargs): log.append(WarningMessage(*args, **kwargs)) self._module.showwarning = showwarning return log else: return None def __exit__(self, *exc_info): if not self._entered: raise RuntimeError("Cannot exit %r without entering first" % self) self._module.filters = self._filters self._module.showwarning = self._showwarning # filters contains a sequence of filter 5-tuples # The components of the 5-tuple are: # - an action: error, ignore, always, default, module, or once # - a compiled regex that must match the warning message # - a class representing the warning category # - a compiled regex that must match the module that is being warned # - a line number for the line being warning, or 0 to mean any line # If either if the compiled regexs are None, match anything. _warnings_defaults = False try: from _warnings import (filters, default_action, once_registry, warn, warn_explicit) defaultaction = default_action onceregistry = once_registry _warnings_defaults = True except ImportError: filters = [] defaultaction = "default" onceregistry = {} # Module initialization _processoptions(sys.warnoptions) if not _warnings_defaults: simplefilter("ignore", category=PendingDeprecationWarning, append=1) simplefilter("ignore", category=ImportWarning, append=1) bytes_warning = sys.flags.bytes_warning if bytes_warning > 1: bytes_action = "error" elif bytes_warning: bytes_action = "default" else: bytes_action = "ignore" simplefilter(bytes_action, category=BytesWarning, append=1) del _warnings_defaults